<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="/static/jquery-1.11.3.js"></script>

    <script>
        //都是同一个函数
        console.log($ === jQuery);
        window.onload = function () {
            var btn = document.getElementById("btn");
            console.log(btn);

            var $btn = $('#btn');

            var $b = jQuery('#btn');

            console.log($(btn));

            console.log($(btn));

            console.log($btn.get(0));
        }
    </script>
</head>
<body>

<button id="btn">按钮</button>
</body>
</html>